Development of kinetochores during early mitosis in HeLa cells and the stability of a trilaminar kinetochore structure
- German Cancer Research Center, Heidelberg (Germany)
The ultrastructure of the kinetochore varies during the course of mitosis. This variation is considered to be a progressive maturation process that may correlate with kinetochore function. We examined the development of kinetochore structures on condensing prophase chromosomes in HeLa cells. Usually, one accepts the three laminar structure of the kinetochore of a condensed metaphase chromosome to reflect the general state and to be a prerequisite for microtubule attachment. The study of developing kinetochores in mitotic cells revealed unquestionable exceptions from this dogma. At the onset of chromatin condensation, indicating the beginning of prophase, the nuclear envelope and the nucleoli are still intact. First indications for kinetochore formation, documented as clouds of a fibrous material or as the {open_quotes}kinetochore ball structure{close_quotes} can be identified along or close to distinct heterochromatic, condensed chromatin elements. These fibrils extend from or interdigitate with the folding chromatin. Enhanced density of the ball structure represents a condensation process. Concomitantly a segregation of a plate structure is detected, occuring at a distal zone but obviously not at the end of the fibrils. This differentiation into kinetochore plate and corona more or less coincides with two other important prophase processes: the first tangential contacts to single microtubules and the mitotic breakdown of the nuclear envelope. But evidence will be discussed that these early prophase features not necessarily depend on each other and that the formation of a characteristic, trilaminar kinetochore structure does not guarantee its function. Conversely, structurally incomplete kinetochores can establish microtubular contacts for the attachment of chromosomes into the spindle.
- OSTI ID:
- 28446
- Report Number(s):
- CONF-9210475-Cond.; TRN: 95:001845-0020
- Resource Relation:
- Conference: NATO advanced research workshop, Crete (Greece), 10-15 Oct 1992; Other Information: PBD: 1993; Related Information: Is Part Of Chromosome segregation and aneuploidy; Vig, B.K. [ed.] [University of Nevada, Reno, NV (United States). Dept. of Biology]; PB: 429 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
The Cell Cycle Timing of Centromeric Chromatin Assembly in Drosophila Meiosis Is Distinct from Mitosis Yet Requires CAL1 and CENP-C
Structure of the DASH/Dam1 complex shows its role at the yeast kinetochore-microtubule interface